The electric motor drives the sewing needle and all such interlockingly driven members as the transport, crochet, needle carrier bar, etc.
The electronic means comprise microprocessors connected, through power transistors, to the electric motor and a number of electrically operated devices within the sewing machine. The microprocessors are suitably programmed to ensure that all the various sewing machine functions are performed correctly by operating and controlling the electric motor and said electrically operated devices.
It has been prior art practice to accommodate such electronic means within a case mounted on one side to the electric motor. The assembly comprised of the case enclosing the electronic means and the electric motor was disposed beneath the work top of a desk mounting the sewing machine.
A serious drawback of such an operation assembly is that the electric motor and power transistors would become overheated under severe operating conditions of the sewing machine. This overheat situation may result in malfunction or even total failure of the electric motor and the power transistors, besides causing discomfort to the operator whose legs would be normally kept close to the operation assembly.
Another drawback comes from the physical size of said operation assembly, which occupies a relatively large proportion of the space available underneath the work top to restrict legroom for the operator. In addition, its size poses some difficulty to the installation of the operation assembly under the machine work top.